1. FIELD OF THE INVENTION
This invention relates in general to the construction of presses and in particular to a new and useful press for the shaping of sheet metal without cutting which includes a crank drive which comprises crank wheels or crank shafts which rotate in respective opposite directions of rotation and which are connected to respective corners of a vertically moving press frame.
2. DESCRIPTION OF THE PRIOR ART
A press having a crank drive which includes a plunger driven by crank wheels through connecting rods and guided tie rods is known. In practice it was found a disadvantage in such a press that the horizontal force component resulting from the crank drive must always be absorbed by the tie rod guide. Another disadvantage in a known press is that the fulcrum or junction of the connecting rod and the tie rod is as a rule arranged outside the guide. This has the result that the horizontal force component exerts an undesired bending moment on the tie rod. Such negative phenomena are particular apparent in presses with a large stroke. In presses of the known type the transmission of the force to the plunger by separate independent tie rods provides no assurance for a plunger movement plane which is parallel to the table surface of the press.